Researchers at Concordia University have developed a new manufacturing method that could make small wind turbines lighter, cheaper, and more efficient.
Their new approach uses a technology called 4D printing to create curved wind turbine blades from flat sheets of carbon-fiber composite material.
The study was published in the journal Polymer Composites.
Small vertical-axis wind turbines are becoming more common in cities and on the rooftops of buildings.
Unlike the large wind turbines seen on wind farms, these turbines have blades that spin around a vertical pole.
They are often chosen for urban areas because they can work in changing wind directions and fit into smaller spaces.
One challenge with making these turbines is producing their curved blades. Traditional manufacturing requires large, specially shaped molds to form the blades. These molds are expensive to make, take time to produce, and can add extra weight and cost to the final product.
The Concordia research team found a clever way to avoid using these complex molds. Instead of shaping the blades directly, they began with flat sheets made from layers of carbon fiber and epoxy resin.
By carefully arranging the direction and order of the carbon-fiber layers, they were able to make the flat sheets naturally bend into the correct curved shape during the manufacturing process.
This technique is called 4D printing because the material changes shape over time after it has been made.
As the flat panels cool after being heated and cured, differences in the material’s internal structure cause them to bend into a carefully designed curved form without needing additional shaping.
To make this possible, the researchers created a new design method. Instead of guessing how different carbon-fiber layers would bend, they first decided on the exact blade shape they wanted. They then worked backwards to calculate the best arrangement of the material layers needed to create that shape automatically.
The results were impressive. The finished composite blades closely matched the shape of commercial aluminum blades but weighed about 80% less. Despite being much lighter, they also performed better in laboratory tests. Wind turbines fitted with the new blades spun faster than turbines using traditional aluminum blades, suggesting they could generate electricity more efficiently.
The researchers believe this new manufacturing process could lower production costs while improving the performance of small wind turbines. Because the method removes the need for expensive molds, it may also make manufacturing faster and more flexible.
Although the research focused on wind turbine blades, the technology could have many other uses.
Lightweight composite materials that can automatically form complex shapes may one day be used in aircraft, vehicles, spacecraft, and many other engineering projects where reducing weight and simplifying manufacturing are important goals.
Source: KSR.
